1. Field of the Invention
The present invention relates to image forming devices, and more particularly, to an image forming device in which a photoreceptor can be replaced easily, and in which it is unlikely that an image problem is caused by a grounding failure of a photoreceptor.
2. Related Background Art
An image forming device typically forms a toner image onto the surface of a photoreceptor, and rotates the photoreceptor to transfer the toner image to a printing medium such as paper, thereby forming an image. When the toner image is formed, the photoreceptor undergoes a charging process, an exposing process, and a developing process. Accordingly, it is necessary for the photoreceptor of the image forming device to be grounded.
In a typical configuration of an image forming device, a drum shaft is fixed to the frame (machine frame) of the body of the image forming device, a photoreceptor is rotatably supported by the drum shaft, and a driving gear rotates the photoreceptor. In this configuration, the photoreceptor rotates, while the drum shaft does not rotate. The drum shaft is made of a metal, and grounded. When the drum shaft is fixed to the machine frame, the grounding of the photoreceptor is secured by bringing the drum shaft and the photoreceptor into conduction by the use of an auxiliary member fixed to the drum shaft. However, since such an auxiliary member does not rotate while the photoreceptor rotates, the use of the auxiliary member may cause such problems that harsh frictional noises are made by the friction between the auxiliary member and the photoreceptor, and that the auxiliary member is worn by the friction, eventually leading to a contact failure, thereby resulting in a grounding failure.
In order to solve such problems, it is common for a photoreceptor and a driving shaft to be integrally formed, and a driving gear simultaneously rotates the driving shaft and the photoreceptor. That is, in this structure, the occurrence of grounding failure is avoided by integrally forming the photoreceptor and the driving shaft, the driving shaft made of metal and grounded, and by bringing the photoreceptor and the driving shaft into electrically conduction. However, in such a structure, it is difficult to replace the photoreceptor. That is, the photoreceptor is a consumable, and needs to be replaced at regular intervals, while the driving shaft being fixed to the machine frame together with the driving gear is not expected to be replaced due to deterioration. If the driving shaft and the photoreceptor are affixed to each other, although it is possible to prevent a grounding failure, the photoreceptor cannot be easily removed. Accordingly, users may not be able to replace their photoreceptors on their own. In such a case, the users are forced to ask professionals to replace their photoreceptors, which incurs extra costs such as service fees, etc.
Given the above-described problems, the present invention is proposed. An object of the present invention is to provide an image forming device in which a photoreceptor can be replaced easily, and in which it is unlikely that an image problem is caused by a grounding failure of a photoreceptor.
According to embodiments of the present invention, there is provided an image forming device comprising: a driving unit including a first coupling member having a groove or a projection for transmitting a rotating force, said driving unit being made of a conductive material, electrically grounded, and rotatable; and a photoreceptor assembly as a driven section rotated by said driving unit, said photoreceptor assembly including a photoreceptor and a second coupling member, and being attachable to/detachable from said driving unit, said second coupling member having a projection or a groove for engaging with said groove or said projection of said first coupling member, rotation of said driving unit being transmitted to said photoreceptor by the engagement of said first coupling member and said second coupling member, and when said photoreceptor is being rotated by said driving unit, said projection or said groove of said second coupling member and said groove or said projection of said first coupling member being electrically connected by a pressured contact with each other, thereby grounding said photoreceptor.
According to embodiments of the present invention, there is further provided an image forming device comprising: a driving shaft which is fixed to a main body of said image forming device, made of a conductive material, electrically grounded, and rotatable; a first coupling member which is made of a conductive elastic material, is fixed to said driving shaft, and has a groove or a projection for transmitting a rotating force; a photoreceptor in a shape of a tube, which is made of a conductive material and is attachable/detachable; and a second coupling member which is made of a conductive elastic material, is fixed to one side of said photoreceptor, and has a projection or a groove that engage with said groove or said projection of said first coupling member, rotation of said driving unit being transmitted to said photoreceptor by the engagement of said first coupling member and said second coupling member, and when said photoreceptor is being rotated, said projection or said groove of said second coupling member and said groove or said projection of said first coupling member being electrically connected by a pressured contact with each other, thereby grounding said photoreceptor.
According to embodiments of the present invention, there is further provided an image forming device comprising: a driving shaft which is fixed to a main body of said image forming device, made of a conductive material, electrically grounded, and rotatable; a first coupling member which is made of a conductive elastic material, is fixed to said driving shaft, and has a groove or a projection for transmitting a rotating force; a cartridge including a photoreceptor, a second coupling member, a developer, and a cleaner unit, said cartridge being integrally attachable/detachable, said photoreceptor being in a shape of a tube and made of a conductive material, said second coupling member being made of a conductive elastic material, being fixed to one side of said photoreceptor, and having a projection or a groove to engage with said groove or said projection of said first coupling member, rotation of said driving unit being transmitted to said photoreceptor by the engagement of said first coupling member and said second coupling member, when said photoreceptor is being rotated, said projection or said groove of said second coupling member and said groove or said projection of said first coupling member being electrically connected by a pressured contact with each other, thereby grounding said photoreceptor, said developer depositing a toner on said photoreceptor so that a latent image becomes a visible image, and said cleaner unit cleaning the toner remaining on said photoreceptor.